Add ScopedMacRTL class for Cocoa browser RTL testing

ui/base/cocoa/rtl_util.h

Index: ui/base/cocoa/rtl_util.h
diff --git a/ui/base/cocoa/rtl_util.h b/ui/base/cocoa/rtl_util.h
new file mode 100644
index 0000000000000000000000000000000000000000..58d7a0351a4eeb705c1f5888e16a6aea8b3b5b66
--- /dev/null
+++ b/ui/base/cocoa/rtl_util.h
@@ -0,0 +1,28 @@
+// Copyright (c) 2016 The Chromium Authors. All rights reserved.

[Robert Sesek, 2016/12/07 16:09:59]

nit: No (c) in new files.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_BASE_COCOA_RTL_UTILS_H
+#define UI_BASE_COCOA_RTL_UTILS_H

[Robert Sesek, 2016/12/07 16:09:59]

_utils files have a tendency to turn into a dumping ground. Can this be
rtl_feature.h ?

+
+#include "base/feature_list.h"
+#include "ui/base/ui_base_export.h"
+
+namespace cocoa_rtl_util {

[Robert Sesek, 2016/12/07 16:09:59]

nit: blank lines around the inside of the namespace

[Robert Sesek, 2016/12/07 16:09:59]

namespace ui

+UI_BASE_EXPORT extern const base::Feature kExperimentalMacRTL;

[Robert Sesek, 2016/12/07 16:09:59]

nit: blank line after

+// Returns whether both:
+// 1) Experimental Mac RTL support is enabled via the ExperimentalMacRTL
+//    feature;
+// 2) The browser UI is in RTL mode.
+// If ExperimentalMacRTL becomes the default, this function can be replaced with
+// uses of base::i18n::IsRTL().
+UI_BASE_EXPORT bool ShouldDoExperimentalRTLLayout();
+
+// Returns true if ShouldDoExperimentalRTLLayout() is true and the OS is
+// 10.12 or above. macOS 10.12 is the first OS where the native stoplight
+// buttons are reversed in RTL, so manually reversing them in previous
+// OSes would make Chrome stick out.
+UI_BASE_EXPORT bool ShouldFlipWindowControlsInRTL();
+}  // namespace cocoa_rtl_util
+
+#endif  // UI_BASE_COCOA_RTL_UTILS_H